The # symbol specifies that the selector is which type?

The # symbol in CSS is specifically used to select an element by its unique identifier, known as the id. Each element in an HTML document can have an id attribute, which is meant to be a unique identifier for that element. When you use the # symbol followed by the id name in your CSS, you are telling the browser to apply the specified styles only to the element that has that corresponding id.

For instance, if you have an HTML element like <div id="header"></div>, you would use #header in your CSS to style that particular div. This allows for precise targeting of elements, ensuring that styles are applied only to those elements with the matching id.

Understanding that the # symbol is linked to the id attribute is important for organizing and controlling styles in your web development projects, as it promotes clarity and maintainability in your CSS.